Piston Ring Land and Bosses Damages

Piston Ring Land and Bosses Damages Points : piston ring land and bosses damages, piston problems, problems in internal combustion engines, ic, engine There are several piston defects. Slap is a sharp noise due to piston being a loose fit in the bore and rocking on the thrust of the power stroke. Seizure is due to the friction on the bore tearing up, the surface of the piston, due to it being too tight in the cylinder. ‘Seized rings’ in the state where the lands arc burred over, gummed, or carboned so that the rings stick in the grooves and let gas ‘blow by’. Pumping, or ring flutter, occurs when the rings are too loose in their grooves and move up and down the piston, forcing oil to behind them. Rap can occur when the gudgeon pin bosses are worn.

In order to prevent the escape of gases past the rings it is necessary to arrange for the latter to exert a certain radial pressure outwards against the cylinder walls. This pressure is only sufficient for the purpose during the normal working conditions for excessive pressure reduces engine power and also gives rise to greater cylinder wear. Ring clearance is provided to allow for expansion when the engine is al. its normal working temperature.